Just a quick note for anyone that might run into the same problem as I did today: if you have an Asus P6T Deluxe V2 motherboard with the latest BIOS, and you’ve installed 6 GB (or more) of RAM in the system, and you’re only seeing 4 GB at the BIOS level, here’s what you need to do. First, take out half the sticks of RAM, leaving three sticks of RAM in, one in each of the orange RAM slots. Then power up the computer and go int the BIOS – it should see 3096 MB of RAM in the System Information section of the BIOS (it’s at the bottom of the first BIOS screen).
Now, power down the computer, unplug the power cable, and install the next three sticks of RAM, this time in the three black slots. Power up the computer, and go into the System Information section to verify that you have 6136 MB of RAM. That’s it, you’re done! I don’t know what idiot at Asus thought this was acceptable to ship a product where you can’t install all the RAM at once, but there you have it.
Remember too that you’ll see to be running 64-bit Vista or Windows 7 in order to access more than 3.5 GB of RAM.